Originally i just did it to make them look cool but i thought of A Cooler reasoning for it..

My two time design is a cat and When cats have their ears down obviously it signifies They are in distress , so I imagine At some point they DID have their ears up but after sacrificing Azure they would permanently go flat from the regret, guilt and because of the fact Azure actively wants vengeance on them for taking his life (Which would presumably make them at least a little anxious)

Kinda similar for the hair streaks..i think it would be also After killing azure And maybe even something like the spawn giving them white streaks in their hair to symbolize their sacrifice since I Give them more white streaks when drawing them in their 2nd life